The present invention relates to a keyboard having at least two parallel columns of keys, and in particular, to a finger-operated mini-keyboard for electrical or electronic devices, wherein the non-depressed keys within one column project the same height from a front plate of the keyboard.
In the course of the increasing miniaturization of electrical or electronic devices, there inevitably arises the requirement for a miniaturized keyboard as well. Primarily, such keyboards are numerical keyboards including 10 keys that are marked with the numbers 0 to 9 of the decimal system. Sometimes additional keys are also provided for special functions. Standard keyboards of this type have evolved which have 12 or 16 keys. In 12-key keyboards, the keys ar arranged in three parallel adjacent columns of four keys each and, in 16-key keyboards, in four parallel adjacent columns of four keys each. The positioning of the keys in the individual columns is such that each key of each column of keys lies on a straight line that extends at a right angle to the direction of the columns and leads to a key of an adjacent column, thereby forming parallel rows. The arrangement of the keys is such that each key lies at the approximate point of intersection of an imaginary straight line of a uniform grid.
The trend toward increasing miniaturization of such keyboards adversely affects the reliability of finger operation.